Pedestrian-vehicle impact events are unfortunate but known occurrences. It is known that in a pedestrian collision, eighty percent of serious injuries occurred to the pedestrian's head while thirty-seven percent of moderate injuries were suffered by lower extremities. (Crandall et al., “Designing Road Vehicles for Pedestrian Protection,” BMJ [formerly British Medical Journal], 324 [7346], pp. 1145-1148)
It is common for the pedestrian's body to be moved by the impacting vehicle such that the pedestrian's head impacts upon the vehicle's engine hood. In an effort to reduce or eliminate injury to the pedestrian's head in a pedestrian-vehicle impact event, automotive vehicle designers developed vehicle systems in which either the trailing edge of the vehicle engine hood is raised and, or alternatively, an airbag is deployed from beneath the trailing edge of the vehicle hood.
Both approaches to lessening the injuries to the pedestrian's head require a sensing system mounted in association with the vehicle bumper. Typically this sensing system is fitted to the bumper in an area adjacent to the energy absorber and behind the soft, polymerized fascia at the front of the vehicle. The fascia thus covers the components of the sensing system.
While the sensing system discussed above is suitable for most passenger cars or sport utility vehicles which incorporate fascias as part of their front end design, no similar arrangement is known for vehicles, typically trucks, that have metal bumpers. Without a pedestrian impact sensing system, it may not be possible to provide such vehicles with effective systems that can protect the head of the impacted pedestrian from serious injury.
Accordingly, there is a need for a practical and effective system to protect pedestrians in a pedestrian-vehicle impact event involving a vehicle having a metal bumper. As in so many areas of vehicle technology, there is always room for improvement related to the protection of pedestrians in a pedestrian-vehicle impact event.